'Splain It to Me

I've started Heart Rate Training. First thing I did was figure out my max heart rate by doing a 3-minute step test (outlined in the handy TIMEX book that came with the HRM they gave me): step up and down on a 8-inch step for 3 minutes, get a number, add 45 to it (45 if you're of average fitness, 55 if excellent) = 179. Just for kicks I checked out this NEW IMPROVED formula and got 172. (208 - .7(your age))

To run faster, you have to run faster. Can we all agree on this?

Here are my target heart rate zones (according to the same book):

z1 90-108 bpm
z2 108-126
z3 126-144
z4 144-162
z5!!!REDLINE ABORT ABORT ABORT!!! 162-180

When I run, my heart rate shoots to above the high end of z5 immediately, proving that 179 is most definitely NOT my Max Heart Rate. I slow down. I slow down more. I sloooooow waaaaay down. I'm now doing 12:30 min miles and I'm at the high end or above, of z4.Z4!!!

It gets worse. In spin class last week, my average heart rate was 166 and my max? 213. TWO HUNDRED THIRTEEN.

I had to stop. I could barely keep it under 180.

But the funny thing is I don't feel like I'm dying or anything.

Saturday while running? Average: 155 / Max: 176. And that was doing 12:28 minute miles, cuz if I went any faster, I was quickly in the 180s and above.

So, to summarize:
To run faster you have to run faster.
To run efficiently, you have to train your body to use fat so you have to stay in the correct zone (2 & 3) (??? Something like this??)
To stay in the correct zone, I have to run slower.
Which means, I'm not running faster.

Have I got this right?

So, tell me please: HOW THE HOLY HELL DOES THIS MAKE ME FASTER??